In a video tape cartridge such as that shown in FIG. 1, a cartridge case 1 is provided in its front surface with a tape-protecting front lid member 10 which is locked in a closed position when the tape cartridge is not used, for covering and protecting the recording surface of a video tape 2 extending along the front surface of the cartridge case 1. Between one of the side walls 15 of the cartridge case 1 and one of the connecting members 12 of the front lid member 10 which is opposed to the one of the side walls 15, there is defined a clearance 21 (see FIG. 2) for containing a locking member. The locking member functions to lock the front lid member 10 in a closed position in such a manner that, when the video tape cartridge is mounted in a video tape recorder, a locking release member provided in the video tape recorder (not shown) is inserted in the clearance 21 from the front side of the cartridge case 1 to be engaged with the locking member contained in the same, thereby releasing the front lid member 10 from the locked position.
However, since the clearance 21 is defined in a limited space between the side wall 15 of the cartridge case 1 and the connecting member 12 of the front lid member 10 and is extremely narrow in width, it is rather difficult to insert the locking release member in the clearance 21. Particularly when the video tape cartridge is mounted in the video tape recorder in a condition slightly deviating in either the right or left direction, the locking release member cannot be inserted in the clearance 21. Such inconvenience frequently arises as the video tape cartridge is made smaller with the clearance 21 being narrowed in width.